Fracture plating

ABSTRACT

A plating system for mending a periprosthetic fracture is provided. The system includes an intramedullary rod, a first and second plate, and a plurality of fasteners. The intramedullary rod has a plurality of transverse holes. The first and second locking plates each have a plurality of openings and is configured to have a contour similar to a surface of a bone to which the plate is applied. Also provided is method of mending fractures by using the disclosed system. In the implanted condition, the first and second locking plates are placed across the periprosthetic fracture and each of the plurality of fasteners is inserted through one opening of the first and second plurality of openings and one transverse hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/562,940, filed Dec. 8, 2014, the disclosure of which is incorporatedherein by reference in its entirety for all purposes.

FIELD OF THE INVENTION

The invention relates to plates that are surgically implanted, inparticular, plates that are implanted to mend periprosthetic fractures.

BACKGROUND

A common problem associated with joint replacement surgery is thedevelopment of fractures around the prosthetic, known as periprostheticfractures. For example in a Total Knee Replacement (TKR) procedure,fractures may occur in the femur around the prosthetic joint implantedat the distal portion of the femur. Various treatments are employeddepending on the severity of the fractures and whether the prostheticbecomes loose. The fractures generally occur as a result of trauma orinfection and in extreme cases may require additional surgicalprocedures in order to re-align the prosthetic knee and/or applyadditional plates or rods, so that the fractures will heal properly. Inmost cases when a periprosthetic knee fracture occurs, the prosthesisremains well fixed to the bone beneath it and securing the bone to thepart of the femur which has broken away is a challenge.

Mending such fractures is a challenge due to the lack of availablehealthy bone remaining around the location of the fractures. As aresult, fracture fixation may be inadequate and the fracture may healincorrectly causing abnormal stresses on the prosthetic joint, which inturn may cause pain, stiffness, and potential TKR failure. Therefore,there is a need for improved surgical implants to mend periprostheticfractures.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a plating systemfor mending a periprosthetic fracture is provided. The system comprisesan intramedullary rod including a plurality of transverse holes, a firstlocking plate having a first plurality of openings and configured tohave a contour similar to a first surface of a bone, and a second platehaving a second plurality of openings and configured to have a contoursimilar to a second surface of the bone. The system further includes aplurality of fasteners, wherein in the implanted condition, the firstand second locking plates are placed across the periprosthetic fractureand each of the plurality of fasteners is inserted through one openingof the first and second plurality of openings and one transverse hole.

According to another embodiment of the present invention, a method ofmending a periprosthetic fracture is provided. The method comprisesapplying a first locking plate to a first surface of the bone across theperiprosthetic fracture, the first locking plate having a firstplurality of openings and configured to have a contour similar to thefirst surface of a bone, applying a second plate to a second surface ofthe bone across the periprosthetic fracture, the second locking platehaving a second plurality of openings and configured to have a contoursimilar to the second surface of the bone, inserting an intramedullaryrod having a plurality of transverse holes into the medullary cavity ofthe bone, and attaching the first locking plate to the second lockingplate via plurality of fasteners. Each of the each of the plurality offasteners is inserted through one opening of the first and secondplurality of openings and one transverse hole.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a front cross-sectional view of a first embodiment of theinvention in the installed condition;

FIG. 2a is a side plan view of fracture plate included in a systemaccording to another embodiment of the present invention;

FIG. 2b is a front view of the fracture plate of FIG. 2a ; and

FIG. 2c is a cross-sectional view of the fracture plate along axis c-cin FIG. 2 b.

FIG. 2d is a cross-sectional view of the fracture plate along axis d-din FIG. 2 c.

DETAILED DESCRIPTION

The invention will now be described by reference to exemplaryembodiments and variations of those embodiments. Although the inventionis illustrated and described herein with reference to specificembodiments, the invention is not intended to be limited to the detailsshown and described. Rather, various modifications may be made in thedetails within the scope and range of equivalents of the claims andwithout departing from the invention.

Generally, various embodiments of the present invention provide a meansfor mending periprosthetic fractures. The means for mending theperiprosthetic fractures may comprise locking plates that may beconfigured for attachment to a plurality of bone fragments separated bya fracture. The locking plates assist in fixing the bone fragments intheir relative position by preventing movement of the fragments relativeto one another within the six degrees of freedom. The locking plates maybe implanted by attaching at least two plates to the bone fragmentsacross a periprosthetic fracture, preferably on opposing sides of thebone. The locking plates may be contoured, so that the locking plateswill follow the contour of the bone to which the locking plates areapplied. The locking plates may also be configured to be implanted inclose proximity to a prosthetic joint without touching the prosthesis,such that the locking plates do not interfere with the operation of theartificial joint.

Referring now to FIG. 1, an exemplary embodiment of a plating systemaccording to the present invention is illustrated comprising a medicaldevice that is surgically implanted onto the bone 12 and spans afracture 8 in order to treat, for example, a distal femoral fracture.

The plating system of the embodiment of FIG. 1 comprises two lockingplates 13 a, 13 b, applied to opposing sides of the distal end of afemur 12 near the femoral component 10 of a prosthetic knee. In FIG. 1,one of the locking plates 13 a may be applied to the medial side of thefemur on the bone fragments 9 a, 9 b of the bone 12, while the otherlocking plate 13 b may be also be applied to bone fragments 9 a, 9 b,but on the lateral side of bone 12. Locking plates used in systemsaccording to the present invention are not limited to attachment to thematerial and medial sides of the bone. The plates may be configured forattachment to any side or section of a bone, as long as the lockingplates are installed across a fracture with one end section attached toa first bone fragment and a second end section of the locking plateattached to the second adjacent bone fragment.

The system may further comprise an intramedullary (IM) nail or rod 11.An IM rod, as known by those of skill in the art, is a metal rod forcedinto the medullary cavity of a bone. IM rods assist in fixing thefragments of a bone separated by a fracture. The IM rod 11 may have aplurality of transverse holes extending through the rod to accommodateone or more fasteners 15 a, 15 b. The fasteners are preferably providedin the form of transfixing bolts. Inserting one of the fasteners 15 athrough the first bone fragment 9 a on one side of the fracture 8 andthe second fastener 15 b through the adjacent bone fragment 9 b on theother side of the fracture 8 may prevent rotation of the bone fragmentsrelative to one another about the longitudinal axis of the IM rod 11.This rotation may be referred to as yaw, one of the six degrees offreedom. The fasteners 15 a, 15 b may also assist the IM rod 11 inpreventing the fragments from separating from each other along thelongitudinal direction of the IM rod 11.

Referring to the cross-sectional view illustrated in FIG. 1, thecombination of the fasteners 15 a, 15 b and the IM rod 11 may preventmovement in two of the six degrees of freedom. However, the combinationof the fasteners 15 a, 15 b and the IM rod 11 may not sufficientlyminimize or eliminate relative movement between the two bone fragments 9a, 9 b in the X-direction (left to right) or the Z-direction (forwardand back). Rotation about the X-axis and the Z-axis (pitch and roll) mayalso not be sufficiently prevented by the combination of the IM rod 11and fasteners 15 a, 15 b. In order to minimize or eliminate thepotential relative movement for all six degrees of freedom between thebone fragments 9 a, 9 b, it is preferable that the transfixing bolts 15a, 15 b are also inserted through openings 17 a, 17 b in the lockingplates 13 a, 13 b.

The locking plates 13 a, 13 b may be compressed against the bone 12. Inone embodiment of the present invention, the compression may be achievedby inserting each fastener 15 a, 15 b through a corresponding opening 17a, 17 b in each locking plate 13 a, 13 b and through a hole in the IMrod 11. It is preferred that the spacing between the holes in the IM rod11 is about the same as the spacing between the openings in each of thelocking plates 13 a, 13 b. This ensures that the transfixing bolts 15 a,15 b are relatively perpendicular to the longitudinal axis of the IM rod11 when installed. The diameter of the head of the fasteners 15 a, 15 bmay be larger than the diameter of the openings in each locking plate 15a, 15 b. This will allow the transfixing bolts 15 a, 15 b to be insertedin either direction. A nut 16 a, 16 b may then be screwed on theopposing end of each fastener 15 a, 15 b. The nut, like the head of thefasteners 15 a, 15 b, may have a diameter larger than the opening of thelocking plates 13 a, 13 b, so that a compressive force on either side ofthe locking plates 13 a, 13 b is generated when the nuts 16 a, 16 b aretightened. The fasteners 15 a, 15 b preferably include some feature thatwill prevent the nuts 16 a, 16 b from slipping to maintain thecompressive force generated once set by a user. The feature shouldprevent the loss of compressive force for at least as long as necessaryfor the fracture to heal. Such features may include the standardfeatures associated with a locknut or lock washer as are known in theart, a set screw inserted through a tapped hole in the nut perpendicularto and in contact with the shaft of the fastener, or any feature capableof providing the desired functionality.

As mentioned above, it is preferred that the locking plates 13 a, 13 bare manufactured to be attached as close to the prosthetic joint 10 aspossible, so that extreme distal and proximal fractures in the bones maybe repaired. To enable attachment close to the prosthetic joint, thelocking plates 13 a, 13 b may be contoured to match the contour of thebone to which it is attached. For example, in the embodiment illustratedin FIG. 1, the locking plates 13 a, 13 b each include a bent section 14a, 14 b that may be applied around and over at least a portion of eitherthe medial or lateral condyle of the femur 12.

Referring now to FIGS. 2a to 2c , a locking plate 20 according toanother embodiment of the present invention may include a plurality ofopenings 22 for receiving a fastener and a blade 24 to enhance the gripof the device on the fractured bone. The blade 24 may be located on atleast one end portion of the locking plate 20. A cross-sectional view ofan exemplary blade 24 along axis c-c in FIG. 2b is illustrated in FIG.2c . A cross-sectional view of an exemplary blade 24 along axis d-d inFIG. 2c is illustrated in FIG. 2d . The blade 24 may include two ¼ inchend projections roughly 8 mm apart resulting in a cross-section that is‘C-shaped’ when viewed in the cross section of FIG. 2c . The length ofthe blade is preferably about 1″ to 2″ long. The C-shaped structure ofthe blade 24 is preferred as it minimally disrupts existing bone whilemaximizing the area-moment of inertia because the C-shaped blade 24 willmore closely resemble the outside curvature of the bone at the locationin which the blade is to be inserted. The blade 24 once inserted intothe bone and following insertion of a fastener, such as a transfixingbolt, through one of the plurality of openings 22 will prevent thelocking plate 20 from rotating or pivoting on the surface of the bone.

The transfixing bolts may provide a dual fixation aspect whereby thebolts compress the locking plates pushing the blade into the bone, sothat the end of the locking plates grip the distal end of the bone andsimultaneously, the bolts exert additional stability through compressionas described above. Finally, the blade may be a separate piece attachedto the plate with an additional fastener inserted, for example, throughany of the holes in the locking plate. A separate blade allows thesurgeon performing the periprosthetic fracture repair procedure toselect the position of the blade and customize the location at which theblade may grip the bone.

In yet another exemplary embodiment of the present invention, a methodof mending a perisprothetic fracture is provided. The method maycomprise first inserting an IM rod into the medullary cavity of the bonehaving the fracture, followed by placing locking plates across thefracture on either side of the bone. The locking plates may then befastened together by using one or more fasteners, such as transfixingbolts. Therefore, a user may select one or more from a plurality ofopenings in each locking plate through which a fastener may be inserted,ensuring that the fastener is also inserted through a transverse hole inthe IM rod. After the one or more fasteners are inserted through thelocking plates and the IM rod, a compressive force is applied to thelocking plates in order to hold the plates in position on the surface ofthe bone. Preferably, the fasteners holding the locking plates inposition are oriented perpendicular or approximately perpendicular tothe longitudinal axis of the IM rod.

It is preferred that the locking plates and the IM rod include aplurality of openings to receive the fasteners to allow the surgeon tocustomize the location of the plates along the bone. In FIG. 1, forexample, the locking plates 13 a and 13 b have been placed at the sameheight on the bone 12. However, embodiments of the present invention mayinclude locking plates that a configured to be moved independently ofone another either distally or proximally along the bone according tothe needs of the patient and the location and severity of the fracture.In general, when mending a periprosthetic fracture, the medial lockingplate will be slightly further distal than the lateral locking plate. Anaspect of a fracture plating system according to the present inventionis that the femoral component may be restored to its correct positionand rigidly fixed in place to allow the fracture to heal by providingimproved and reliable alignment of the bone, such as a femur in thecoronal and sagittal planes.

While preferred embodiments of the invention have been shown anddescribed herein, it will be understood that such embodiments areprovided by way of example only. Numerous variations, changes, andsubstitutions may occur to those skilled in the art without departingfrom the spirit of the invention. Accordingly, it is intended that theappended claims cover all such variations that fall within the spiritand scope of the invention.

I claim:
 1. A plating system for mending a periprosthetic fracturecomprising: an intramedullary rod including a plurality of transverseholes; a first locking plate having a first plurality of openings andconfigured to have a contour similar to a first surface of a bone; and asecond plate having a second plurality of openings and configured tohave a contour similar to a second surface of the bone; a plurality offasteners; and a plurality of nuts, each nut being configured to beattached to an end of a respective fastener of the plurality offasteners, wherein in an implanted condition, the first and secondlocking plates are disposed across the periprosthetic fracture and eachof the plurality of fasteners extends through one opening of the firstplurality of openings, another opening of the second plurality ofopenings, and one transverse hole, and is attached to one of theplurality of nuts, wherein at least one of the first and second lockingplates include a bone gripping mechanism, the bone gripping mechanismcomprising a blade having a free end configured for insertion into thebone, wherein the blade comprises two projections and a C-shaped web ofmaterial extending in a width direction between the two projections andextending in a length direction along said two projections to the freeend of the blade, each projection having a greater thickness than theC-shaped web of material.
 2. The plating system of claim 1, wherein thebone gripping mechanism is configured to be set at a user-selectedlocation on one of the first and second locking plates.
 3. The platingsystem of claim 1, wherein the plurality of fasteners are configured tocompress the first and second locking plates toward one another when ina tightened configuration.
 4. The plating system of claim 3, wherein theplurality of fasteners are configured to maintain a force of compressionuntil at least the fracture is healed.
 5. The plating system of claim 1,wherein the plating system is configured to prevent relative movement ofbone fragments within six degrees of freedom.
 6. The plating system ofclaim 1, wherein the intramedullary rod has a longitudinal axis and inthe implanted condition the plurality of fasteners are perpendicular tothe longitudinal axis.
 7. The plating system of claim 1, wherein theplating system is configured to be implanted in proximity to aprosthesis such that in the implanted condition the first locking plateand second locking plate do not touch the prosthesis.